Jim Avila, ABC news, New York. We move next to a health alert about how to survive a heart attack. One factor may be the day and time of day it happens. Today, the respected mayo clinic took a look at what happens in your emergency room. And ABC's chief medical editor, Dr. Richard Besser, lays out what patients should know. Reporter: Crushing pain. A blackout. The race to get to the hospital. You are trying to survive a heart attack. But if you arrive at the hospital at night, or on the weekends, you have a 5% higher chance of dying. That means an extra 2,000 deaths a year. It's not that the heart attacks are any different. It's just the timing. The mayo clinic looked at the records of 2 million heart attack patients, from 42 studies. The key to treating their type of heart attack? A balloon that clears their clogged artery. But those arriving to the E.R. At night, or on the weekend, received that treatment 15 minutes later than those who came during Normal business hours. There are fewer staff or resources at night or weekends. That's true. Reporter: Meaning the solution could be as simple as staffing. So, rich is here. This is about staffing at hospitals? What's a patient to do? Well, the first thing. If you think there's any chance you're having a heart attack, dial 911. You never want to drive yourself to the hospital. And if you happen to live near a teaching hospital, you're in luck. They tend to be better staffed, particularly at night. But something everyone can do. If you think you're having a heart attack, chew an aspirin. It's going to thin your blood and improve your chance of surviving. That's something you can do immediately. Thank you, Richard Besser,

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